The present invention relates to a light-emitting element driving apparatus and method for driving plural light-emitting elements in a time sharing driving manner, and a projector using such apparatus and/or method.
In conventional projectors, for example, a field sequential color system and color image synthesis system are used to project color images.
In the field sequential color system, a red image (R image), green image (G image), and blue image (B image) are projected onto a screen sequentially and periodically at a so high switching speed that human eye can visually recognize one color image. A projector of a field sequential color system is in practical use, in which DMD (Digital Micro-mirror Device) is used as an optical modulating device for transmitting by means of optical-beam image information output from a personal computer. In the projector, light from a light source is collected onto DMD through a color wheel (color filter) having red, green and blue areas arranged in its rotational direction, and light reflected on the color wheel is projected onto a screen. While the color wheel rotates, DMD is mechanically driven in synchronization with the rotating color wheel so as to correspond to a red image, green image and blue image, and further a red, green, and blue color image component reflected on DMD are projected onto the screen, whereby a color image is composed on the screen.
In recent, a projector of another type has been developed, which uses a red light emitting element (LED), green light emitting element (LED), and blue light emitting element (LED) serving as a light source, and these LEDs are driven successively in a time division driving manner, whereby respective color images are projected onto the screen without using the color wheel (Refer to Patent Document: Japanese Patent No. 2004-311635 A).